Before the harvest plan is set, somebody has to decide which compartments to go and look at. A crew cannot plot every stand every year, so some get measured, some get a drive along the ride with a look up at the canopy, and some are taken as read because the planting year says what they should be. Thinning and clearfell slots then get booked against that.
A stand that grew slower than its age class suggests gets thinned early, or a fast one waits a season it did not need to. You find out when the contractor is on site.

